Original post by: Robin Walters ,
You likely need to de-register your phone first. Please follow the troubleshooting steps below:[br] [br] NOTE: Handset must be in idle mode when performing the following procedures.[br] [br] On the old handsets,[br] [br] 1. Press MENU/SELECT button then press *7890#.[br] 2. Press ▼CID or ▲DIR until it shows “TO TEST HANDSET”, then press MENU/SELECT button.[br] 3. Press ▼CID or ▲DIR until it shows “TO DE-REGISTER CLEAR”, then press MENU/SELECT button twice.[br] 4. Hold down the OFF/CANCEL button until the display shows “OUT OF RANGE OR NO POWER AT BASE” or “Press HS LOC on base 4 sec”, then press MENU/SELECT button.[br] [br] After this step, please reset the handset by taking the battery out for a minute then plug the battery back in.